Film gauge control



April 9, 1940; c. LYNG FILM GAUGE CONTROL Filed March 11, 1937 INVENTOR Cars'ren Lang y I T ONE w I A Patented Apr. 9, 1940' i i I UNITED STATES PATENT OFFICE J GAUGE CONTROL Carsten Lyng, Union, N. J., assignor to Celluloid Corporation, a corporation of New Jersey Application March 11, 1937, Serial .No. 130,422

7 Claims. (01. 18--15) 'This invention relates to the method of and feet long, depending upon the thickness of the apparatus for controlling the gauge of cellulose film or foil. derivative films and foils, and relates more par- .The cellulose derivatives used are not always ticularly to a method of and apparatus for measof uniform viscosity or solubility characteristics uring the gauge of. the film or foil immediately so that successive batches of dope may vary in after the dope is applied to the casting wheel, i. e. viscosity. These batches are not mixed one with while the dope is still in liquid "or plastic condithe other but may assume separate layers in the tion. holding tanks with little intermingling. When An object of this invention is the provision of, each lay r e of d p a iv s a the pp 10 an improved method. for controlling the gau e of the rate of feed onto the casting surface will 10 cellulose derivative films or foils, gradually change due to the different viscosity Another object of thisinvention isto provide 0f the d p Such Changes are net Ordinarily novel apparatus for measuring th gauge of th perceptible and would not be detected until ofifilm dope while the same is in liquid or plastic u e a er a s f u d at th sp l. Fur hercondition, y more, the cast dope undergoes lateral and trans- Other objects of this invention, together with verse shrinkage as it loses its volatile solvents, certain details of construction, combinations of and the film is Subjected o tension and Strains parts, will appear from the following detailed in its p s through g d e s. description a d th n ed claims; As the process isv continuous there is no. op-

' In the manufacture of film by the dope castingv p y Checking e gauge f t e fi 20 method, the control of the gauge or thickness of across its Width by the Ordinary o er the film is of utmost importance. For example, methods- It has been D DQ use an p a films for motion picture and photographic work micrometer. the Operation of which d p ds upon are required to be within narrow limits with recertain principles of optics. f ec n the 26 spect to thickness, i. e. a 9.0075 of an inch film gauge of e fi m 0r f Since the Working of will have a tolerance from about, 0.0072 to 0.0078 the Optical micrometer is dependent up t ree of an inch. Variations above. and below these conditions, namely, the angle of nc dence of a limits result in unusable material which must a of light passing t rough the film or foil be scrapped or reworked with attendant increase Whose ga is'being measured, the thickness of 30 in manufacturing costs. "While the largest outthe film Q T011 and theindex i refraction and 30 let, for film is f t graphic use, ther ar material of which it is composed, the optical numerous other applications which have their micrometer a not Whelly Satisfactory, parspecial requirements of closely'controlled gauge. ticularly when thin n foils were being This invention is also applicable in the manui i Heretofore 1t has been the practice, as each roll 35 facture of foils as well as films. Foils are usually considered of a lower order of thickness than was gauge thefilm e Its Wldth wlth films, say, less than 0.003'of an inch, and are hand. mlcromeper If gauge was uneven particularly useful as wrapping materials. 'Here g l i gzgg g g gg fge g ig? 3::

40 again efficient manufacturing operations depend at a reduced mica adjustment was then 40 upon control of'gauge' made in the hopper feed changing the how of T dope castmg i for makmg, films a dope onto the casting surface to give the film or OOmPrises fwmeg dope of umform foil the desired thickness. The adjustment was OS W a b y feedmgi t pe a pp made by trial and error, it being necessary after fr m Which it is Spread means of a p each adjustment to cut and regauge the film at 45 or by extrusion from the nozzle of the hopper onto the winding spool when the first portion affected a continuously moving casting surface which may by the adjustment, arrived there. It often rebe the highly polished face of a large wheel or quired several hours of adjusting, cutting and the surface of an en'dless'belt. In the travel of gauging to arrive at the proper thickness of film the casting surface the volatile solvents in the on the winding spool. During this time there ac- 50 dope evaporate leaving a self-supporting film or cumulated an excessive amount of scrap, making foil which is stripped from the surface, dried or for an uneconomical procedure. seasoned in a hotair chamber and finally wound In accordance with this invention, the gauge on a. spool in a continuous roll. The rolls are of the film or foil at the windingspool may be about 40 incheswide and from'500 to about 4,000 controlled over an extended period of time with- 55 out cutting the film or foil by gauging the thickness of the dope, which ranges from 5 to 10 times the thickness of the resulting film, at various points across its width on the casting surface just after the dope leaves the hopper and adjusting the hopper feed to give a predetermined thickness of dope at the point gauged. The invention comprises, in general, a system of gauging devices for determining the dope thickness at predetermined points across the width of the dope on the casting surface. From the gauge readings adjustments can be made in the hopper feed, the feed of which can be instantly checked. Frequent readings and adjustments assure uniform gauge at the winding spool and cut scrap losses down to a minimum. More specifically, the invention comprises mounting a series of micrometers, say, three or more, across the casting surface near the hopper, the casting surface itself forming the anvil of the micrometers. The micrometer screw is terminated in a pin point which is raised and lowered to contact the dope surface. The dial and pointer of the micrometer indicates the elevation of the pin above the casting surface. Means may also be provided for checking variations in the surface of the casting wheel due to the thermal expansion or contraction of the wheel in relation to the scraper.

In order further to illustrate my invention, reference is had to the accompanying drawing wherein:

Fig. 1 is a front elevational View of my device showing the mounting of a series of micrometer gauges across the casting wheel surface,

Fig. 2 is a side elevational view of my device, taken on the line 2-2 of Fig. 1, showing, partly in cross-section, the construction of one of the micrometer gauges and the relative position of the same with respect to the hopper and the casting wheel,

Fig. 3 is a front elevational View, partly in crosssection, of one of the micrometer gauges, showing the means for raising and lowering a gauge spindle, and

Fig. 4 is a detailed view in cross-section, taken on the line 6-4 of Fig. 3 and showing, on a slightly enlarged scale, the means for adjusting the zero point reading on the dial of the gauge.

Like reference numerals indicate like parts throughout the several views of the drawing.

Referring to Fig. l of the drawing, there is shown the mounting of a series of micrometer gauges, generally indicated by reference numeral 5, with respect to the casting wheel 6. The mounting of the gauges comprises a cross-piece 1 of angle iron, which'is suitably attached to uprights or standards 8 fixed to side castings 9 which also support the film dope hopper l l and a crosspiece l2 of channel iron which is also carried by side castings 9. v

For each dial l3 of the micrometer gauge there is provided on the angle iron cross-piece 1 a bracket Hi suitably secured to said angle iron. The bracket M is adapted to receive the bifurcated ear i5 suitably mounted on the casing of the dial E3, the construction being such that the dial may be adjusted on said bracket relative to gauge spindle 15 of the micrometer gauge.

The cross-piece I2 is adapted to support the gauge spindle it. To this end the flanges i! are provided with openings l8 into which are fitted upper bearing member l9 and lower bearing member 2|, in which bearing members the gauge spindle is adapted to slide freely. The upper end of the gauge spindle is grooved at 22 and the bearing member i9 is provided with a screw 23 having a projection 24 extending into said grooved portion of the gauge spindle for the purpose of preventing the gauge spindle from turning in said bearin members. I j

The upper end of the spindle is also provided with a screw threaded opening 25 adapted to re ceive a screw 26 which is adapted to be raised and lowered with respect to the gauge spindl by means of a knurled head 2'1.

The screw 26 is adapted to cooperate with dial spindle 23 for the purpose of setting the dial at the desired reading. The screw 23 may be set in the adjusted position by means of lock nut 29. The lower end of the gauge spindle is provided with a pin point 3! which is preferably made of copper or stainless steel. The gauge spindle is also provided with an expansible spring 32 which acts against the lower portion of bearing member l9 and a collar 33, which collar is held in position by means of a pin 34. The spring 32 is adapted to force the gauge spindle in a downward direction. For the purpose of raising the gauge spindle there is provided a lever 35, pivoted at 36 on the web 37 of the channel-iron cross piece 52. The lever 35 is provided with a bifurcated end 38 which cooperates with the collar 33 on the gauge spindle H5. The other end 39 of the lever acts as a bearing member for screw 4! which is provided with a knurled head 42 for turning the screw. The screw 4| cooperates with a screwthreaded bearing 43 fixed in a suitable opening in the upper flange of channel-iron crosspiece I2.

In operation, the zero point is taken by lowering the pin 3!, which lowering is effected by turning screw 4! so as to raise the same until it just touches the casting surface of the casting wheel 6. When the film dope 44 is spread as by means of a scraper 45, as is well understood in the art, the pin 31 is again lowered until it touches the surface of the film dope. The reading of the dial is taken and the pin instantly raised and wiped clean. The fine pin scratch on the surface of the film dope quickly flows out and leaves no blemish in the finished film. After readings are made on the several micrometer gauges the hopper feed is adjusted to give at each point the proper film dope thickness, as determined by experiment, for the particular film dope used and the thickness which is required in the finished article. Frequent readings and adjustments can be made without interrupting the casting operation and without cutting the film.

When casting on the wheel, which is approximately 16 ft. in diameter, the radius of the wheel surface may vary a few thousandths of an inch in relation to the scraper by reason of temperature changes or other causes. As a check against such variations a gauge 46 is mounted near the edge of the casting surface at a portion where the surface is not covered by film dope. From the readings on this gauge the zero readings of the dope thickness gauges can be corrected without the necessity of running the gauge spindle down through the film dope to the casting surface. More gauges, such as gauge 45, may be used for checking variations in wheel surface. For example, there may be one dial indication at each edge and one or more at the center of the wheel surface back of the hopper.

It is to be understood that the foregoing detailed description and drawing is given merely by way of illustration and that many variations may of my invention.

surface while the film condition by a measuring instrument which be made therein without departing from the spirit Having described my invention, what I desire to secure by Letters Patent is:

1. Process for the production of film form gauge, which comprises flowing film dope on to acasting surface to form a film, and measuring the thickness of the film on the casting surface while the film dope is still in. a flowable condition by a measuring instrument which scratches the surface of the cast film, the scratch on the surface of the film quickly disappearing due to, the flowing out of the still plastic film dope.

2. Process f0 formgauge, which comprises flowing film dope on to a casting surface to form a film, and measuring the thickness of the film on the casting dope is still in a flowable scratches the surface of the cast'film at a plurality of points across the width thereof, the

scratches on the surface of the film quickly disappearing due to the flowing out of the still plastic film dope. 3. Process for the production of film of uni.- form gauge, which comprises flowing film dope on to a casting surface to form a film, and measuring the thickness of the film on the casting surface while the film dope is still in a fiowable condition by a measuring instrument which scratches the surface of the cast film near the point at which the film dope is flowed on to the casting surface, the scratch on the surface of the film quickly disappearing clue to the flowing out of the still plastic film dope. i

In device for indicating the gauge of film in order to facilitate the control of the gauge,

, the combination with a "casting surface adapted to receive a'film flowed thereon, of means in close proximity to the point at which the casting surface receives the film for measuring the thickness of the film, said measuring means including means co-operating with the casting surface for of unlthe production of film of uniproducing a visual indication on the surface of the cast film while said film dope is still in a fiowable condition. 1

5. 1m a device for indicating the gauge of film in order to facilitate-the control of the gauge,

I the combination with a casting surface adapted to receive a film fiowed thereon, of means in close proximity to the point at which the casting surface receives the film for measuring the thickness ofthe film dope, said measuring means including a pin point which co-operates with the casting surface to gauge the film, between which pin point and the casting surface there is relative motion, said pin point producing a scratch on the surface of the cast film while the film dope is still in a flowable condition.

' 6. In a device for indicating the gauge of film in order to facilitate the control of the gauge, the combination with a casting surface adapted to receive a film flowed thereon, of means in close proximity to the point at which the casting sur-' face receives the film for measuring the thickness of the film dope, said measuring means comprising a spindle terminating in a pin point which co-operates with the casting surface to gauge the film, a micrometer gauge co-operating with said spindle and means for raising and lowering said spindle towards and away from said casting surface.

' 'L'In a device for indicating the gauge of film in order to facilitate the control of the gauge, the combination of a casting surface adapted to receive a film flowed thereon, of means in close proximity to the point at which the casting surface receives said film for measuring the thickness of the film, said measuring means including condition so as to indicate the gauge, and means for measuring the variations of the face of the casting surface.

. CARSTEN LYNG. 

